Japanese Patent Publication No. H10-19899 discloses a blood analyzing apparatus which includes an analyzing operation module for aspirating blood from a blood collection tube used for containing the blood collected from a patient to perform analysis and a transport line for transporting the blood collection tube containing the blood to the analyzing operation module. Sometimes, the contained blood is coagulated in the blood collection tube. When the blood collection tube containing the coagulated blood is transported on the transport line and the blood is aspirated by the analyzing operation module, the nozzle for aspirating the blood becomes clogged. Accordingly, it is necessary to take all the blood collection tubes one by one by an operator's hand in order to confirm whether blood is coagulated and remove the blood collection tube containing the coagulated blood from the transport line.
Japanese Patent Publication No. H11-248853 discloses a coagulated specimen determining apparatus for automatically determining whether blood in a blood collection tube is coagulated without depending on human vision. The coagulated specimen determining apparatus is configured to image the blood in a blood collection tube vertically held and the blood in a blood collection tube tilted at a predetermined angle by a camera, calculate areas of blood portions by binarizing the taken images, and compare a difference between the two areas with a reference value, thereby determining whether the blood in the blood collection tube is coagulated. Moreover, the coagulated specimen determining apparatus is configured to display “there is coagulated matter” on a monitor screen when it is determined that the blood in the blood collection tube is coagulated.
In the coagulated specimen determining apparatus disclosed in Japanese Patent Publication No. H11-248853, it is possible to know whether blood in a blood collection tube is coagulated when a user confirms the display of the monitor screen. However, it is necessary to remove the blood collection tube containing the coagulated blood from a transport line in order to exclude the coagulated blood from the measuring targets. Accordingly, a problem occurs in that operator's time and effort is required. Moreover, in the coagulated specimen determining apparatus disclosed in Japanese Patent Publication No. H11-248853, an area of a blood portion is not accurately proportional to a blood volume in a blood collection tube and a difference between the areas of blood portions in two binarized images changes depending on the volume of blood contained in the blood collection tube. Accordingly, the accuracy of coagulation determination varies depending on the blood volume. In addition, when coagulated matter protrudes from the liquid surface of the blood in a blood collection tube, the liquid surface of the blood is lowered in accordance with an amount of the protrusion. Accordingly, in some cases, the difference between the areas of the blood portions in the binarized images is almost the same as the difference between areas of blood portions in binarized images obtained when blood which is not coagulated is imaged. Thus, in the coagulated specimen determining apparatus, it is impossible to achieve the desired high-accuracy determination of blood coagulation.